1. Field of the Invention
The disclosure is related to a composite having two of principal strengthening compounds and one principal cementing refractory metal, and is specifically related to zirconium diboride (ZrB2) and one carbide combining with the principal cementing refractory metal to prepare a composite with superior hardness and toughness.
2. Descriptions of the Related Art
Conventional cemented carbides are a group of composites composed of WC and Co. In the early 1900s, Henri Moissan synthesized tungsten carbide (WC). Tungsten carbide is of a high hardness, and therefore could be even replacing diamonds in certain applications. However, the tungsten carbide is so brittle and porous that it is not suitable in engineering applications. In 1923, Schröter and Baumhauer found that after being sintered with cobalt or nickel, the tungsten carbide can maintain the hardness of ceramics at no expense of the toughness of metals. Thus, it is beneficial in mould industry. The material has been widely used in different units of cutting tools, mineral extraction and military weapons. About 60% of W consumption is used in producing cemented carbides. In 1930, the demand was 10 tons, and in 2008, it was 50,000 tons, increased by 5000 times in 78 years.
Cemented carbides are with two parts, one is a hardening and strengthening phase, and the other a cementing or binding phase. As described above, when WC is in the strengthening phase it has a high melting point and a high toughness as well as being good in wear resistance. Co in the cemented phase could contribute to a high electrical and thermal conductivity as well as to a high toughness so that the composite is not brittle. In recent studies, hard metals, such as WC and Co, are used as the basis and other carbides such as TiC, TaC and so forth are added to WC, while other binders such as Mo, Ni, Fe and so forth are added to Co, a group of composites, called cermets (ceramics-metals), could be developed. For traditional hard metals, including cermets, the main preparing process is sintering, also allowing for a minute amount of the cemented phase to be incorporated.
However, the composite prepared from the above could be with a variety of choices, and not all the composite having a high hardness and a high toughness can be prepared by using all of the strengthening phase and the cemented phase materials. Therefore, if some certain strengthening materials and some certain cemented materials could possibly result in a composite with a high hardness and a high toughness such a solution undoubtedly might advance the development of the corresponding technology.